We tested 103 adult Ixodes scapularis Say from 12 counties in Minnesota for the presence of Borrelia burgdorferi and the causative agent of human granulocytic ehrlichiosis (HGE), using polymerase chain reaction (PCR). A total of 17 ticks (16.5%) was positive for B. burgdorferi using nested PCR for the flagellin gene, or both PCR for the ospA gene and nested PCR for the flagellin gene. A total of four ticks (3.8%) was positive for the agent of HGE using nested PCR for 16S rDNA. Counties in Minnesota with established and recently reported populations of I. scapularis both had ticks infected with B. burgdorferi. The agent of HGE was only detected in counties with established I. scapularis populations.